a(n) = a(n-1) + sum of base-1000 digits of a(n-1), a(0)=1.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =16a(5) =32a(6) =64a(7) =128a(8) =256a(9) =512a(10) =1024a(11) =1049a(12) =1099a(13) =1199a(14) =1399a(15) =1799a(16) =2599a(17) =3200a(18) =3403a(19) =3809a(20) =4621a(21) =5246a(22) =5497a(23) =5999a(24) =7003a(25) =7013a(26) =7033a(27) =7073a(28) =7153a(29) =7313